For the manner in which men live is so different from the way in which they ought to live, that he who leaves the common course for that which he ought to follow will find that it leads him to ruin rather than safety.-Machiavelli

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Thursday, November 3, 2011

Scrapers

I think the scraper is a misunderstood and underutilized tool. Before I
bought one, I didn't get it. You could tell me about them all day long,
and I'd look at you like a deer staring down a fast moving semi. Fact
is, they are great little tools. It seems to me that the mystery (or
misunderstanding) of them comes from not knowing how to sharpen or use
one. They are simple enough for me to figure out, that means that anyone
can figure them out. Anyway, here's the quick and dirty version...maybe we can go into more detail another day.

The card scraper. A simple piece of saw steel. These come in different sizes and thickness. Thinner is easier to wield, but leaves a wavier surface. Thicker can leave a flatter surface, but can break your fingers. Try different ones to find what suits you...that's the best advice I can give.

Same scraper, other side. Both sides of the working surface should be flat. This is easy enough. Using a long flat file, joint the edge, as straight and flat as you can. The better you do this, the better the scraper will work for you. Next step is to rub it on a stone. Stoning the edge takes off the roughness left by the file. I like to run the sides on a stone as well. Just the first quarter to half an inch is fine. You're only trying to prep the working edge.

This is about the angle that I hold my burnisher. Carbide. Polished. The burnisher raises a burr on the working edge. Here, I'm trying to raise a burr on the right side. Holding the handle at a slight down angle seems to help...you'll find what works best for you. Several light strokes are better than heavier strokes. Did I mention carbide? My workbenbench area is looking pretty cluttered, s'pose I should work on that.

Holding the scraper with both hands, curve the working edge with your thumbs. This takes practice. You can vary the amount of curve by changing the thumb pressure. You will also be able to apply different amounts of down force. Again, this is sort of specific to the application. There's no rule, but light strokes are typically better than heavy. Those are shavings, NOT dust. There is also the matter of finding the right angle to hold it at. This, again, varies. I would imagine that if we looked at this scientifically we'd see a correlation between burr, curve, and angle.

This is a blade for a Stanley 80M cabinet scraper. Cabinet scrapers offer the advantage of a body, sole, and handles. This Stanley blade will typically have 45 degree bevels honed onto each end. I leave a flat on mine, and prepare it in much the same way as a card scraper. You can use it with a burr or without.

Cabinet scraper prepared with no burr. Notice how light the shavings are.

The same scraper, but with a burr. This is a much more aggressive cutting action. Again, application will decide what you need. I like to try on a small piece of scrap to see which will work best for me. You have the option of prepping both sides of the blade in a different manner. No burr on one side, burr on the other. Or different degrees of burr. You could then flip the blade to suit the wood.

If you didn't notice, I'll say it again...much of the use of a scraper depends on you and what you want from the scraper. The real key is in preparation. Having the patience to properly joint and smooth the edge, and draw a burr (but not too big of a burr, now) is what is important. Once you have that figured out, the rest should come fairly easily. I happen to be a little better with the cabinet scraper. It helps to make up for the fact that I have little idea of what the phrase "light touch" means.
The purpose of the scraper, once you've tuned it, is local clean up. They are great for getting at some of those spots of tearout that none of your planes seem to be able to handle. Another great thing is that you can run with or against the grain with them. I have a piece of curly maple that has a couple of really tough areas with serious grain reversal. It's much easier to scrape it in a couple directions than to move my planes around it. I've run into spots that even my 5", 55 degree smoother doesn't want to clean up, but the scraper seems to tame just fine. The final finish will not always be quite as smooth as a plane can achieve, but the tearout will be gone.
Hope this helps!

About the Monastery...

The ill guided adventures of a burned out hooligan as he builds weird choppers and bakes delicious desserts. Along the way, he meets a stunning cast of characters and has adventures in motorcycles, cooking, and machine tools. Will he find salvation? Will he find the question to the ultimate answer? Who knows, but stay tuned...someone might get drunk and spill the beans.